Revision to Tripoli Rule Regarding Wireless Remote Switches

ThirstyBarbarian said:

I see the prep at pads or special prep area solution as the least viable. The workflow will never work. You can’t get a pad assignment and then have a half hour or more of work to do afterward. No one would stand for that.

The two clubs I fly with are big and already have a large number of pads. One has 2 banks of either 6 or 8 pads each (can’t remember for certain), so 12 or 16 at every launch. And the other sets up 1 or 2 banks of 8 depending on turnout, so 8 or 16.

When you get a pad assignment, you need to get out there, set up, and clear out efficiently. You do not want to be the one holding up the entire bank of 6-8 fliers. And it’s not just that people are being impatient — for some fliers, once their rocket is ready, it’s burning the batteries and needs to fly before they are gone.

And how many tools and materials are you going to have to lug out to the pads with you?

It seems like a totally impractical idea.

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^^^^THIS!^^^^

A

ThirstyBarbarian said:

I see the prep at pads or special prep area solution as the least viable. The workflow will never work. You can’t get a pad assignment and then have a half hour or more of work to do afterward. No one would stand for that.

The two clubs I fly with are big and already have a large number of pads. One has 2 banks of either 6 or 8 pads each (can’t remember for certain), so 12 or 16 at every launch. And the other sets up 1 or 2 banks of 8 depending on turnout, so 8 or 16.

When you get a pad assignment, you need to get out there, set up, and clear out efficiently. You do not want to be the one holding up the entire bank of 6-8 fliers. And it’s not just that people are being impatient — for some fliers, once their rocket is ready, it’s burning the batteries and needs to fly before they are gone.

And how many tools and materials are you going to have to lug out to the pads with you?

It seems like a totally impractical idea.

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All of that can be avoided with good design.

jderimig said:

A

All of that can be avoided with good design.

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I was responding to the suggestion that if you can’t or don’t want to change your design, the solution is to go to the pre-flight check in before connecting your batteries, and then connect them at the pad or special preparation area, which would entail basically doing a lengthy prep after checking in. I’m saying that’s not practical, meaning the only practical solution that is really on the table is to change your design if you are currently using wireless remote switches. And I think that’s what you are saying too.

I havent seen this much drama since visiting my 9 year old niece. It's not complicated. They dont want people with energized electronics involved with deployment charges crowded around the RSO table. Solution is to put a switch on the battery line JUST LIKE EVERY OTHER DUAL DEPLOY ROCKET THAT DOESNT USE WIFI! Which is still the majority of the fliers out there. Its simple, its safe and it works. No one needs to disassemble their rockets ebay at the pad. Put in a switch accessible from the outside of your ebay LIKE EVERYONE ELSE DOES!. You can even turn them on before its on the pad making it even easier then it is for everyone else.

jderimig said:

A

All of that can be avoided with good design.

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I beg to differ. Design is only a fractional contributor. It is about the logistics of a launch and traffic engineering. Take Airfest or Midwest Power with 300+ flyers. They all prep in parallel and get RSO'd almost at random. After leaving the RSO table or sometime later they get in line to get to the pads, say 15 to 20 deep. Regardless of the bank, often it takes 15 to 20 minutes to get the rockets ready to launch, sometimes quite a bit longer if there is an electronics issue. Currently it is only sliding the rocket on a rail/rod and activating a couple of switches and listening to beeps. Now, at least with high performance and staged rockets, maybe others, you will need to either do partial assembly at the pad or get on ladders or both. If you want to achieve the performance or flight profile this cannot be eliminated. Those 15 to 20 people may equate to 3 to 5 that need pad-adjacent table access, likely sequentially unless you have an extremely large table. The previous 15 to 20 minute bank loading will now double even if the 3 to 5 can finish assembly, climb, etc. in ~4 minutes each. My guess it will take much longer, again with those rocketeers under undo pressure and now prone to mistakes. So now the lines at the LCO table go from 15 to 20 deep to 30 to 40 deep, adding further pressure to the squeeze point at the bank. This intermediate pad-adjacent table solution is both unreasonable and dangerous. Let's say you eliminate the table, you still have 3 to 5 prepping on the ground, albeit in parallel, but under non-ideal conditions with pieces laying all over the pad bank--even more unreasonable and dangerous.

Actually, I guess one solution is to no longer attend large launches. That would solve the queuing issue.

dshmel said:

I will ask a glaringly naive question. How can Tripoli approve wireless remote switches that are user assembled? And before you say: "motors are certified predicated on proper assembly by the end user following provided manufacturers instructions", I would argue that soldering a board with many components is far more complicated than assembling a motor.

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I'm going to assume for discussion that you're referring to eggtimer kits, and not self-designed/self-made altimeters.

Since an eggtimer kit has switching done via electronics, I can see these failure modes:
1. Software programming failure... basically the code causes an event (or fails to cause an event) incorrectly.
2. Component failure.. technical problem with one or more of the components, causing them to act in an unplanned way
3. Assembly error.. something was assembled wrong in building the altimeter.. soldering, switched components, bridges, etc.
4. Usage error.. something wrong with the usage of it- battery not wired up correctly, av bay wiring errors, etc.
5. Environmental error... something about the operational environment causes an unforseen problem- humidity, temperature extremes, dropped too hard before launch etc.

I would argue in this case that #1, #4, and #5 are not unique to eggtimer products, and are problems that could be seen with commercial altimeters.

As for #2
2.1 Component failures could be present in any altimeter- quality control out of the box basically. I guess you could say that this is a problem that's not unique to eggtimer products.
2.2 Component failure could happen based on #3 above (soldering looks good, but maybe a component was damaged by heat). I'll presume for the sake of discussion that this is more likely in a self assembled altimeter than commercially bought. More on this further down.

For #3.
3.1 Assembly error is caused by vague or incorrect instructions- basically the user is doing everything incorrectly, but the written procedure is wrong or not clear enough
3.2 Assembly error caused by soldering activity. User is following instructions, but assembles the circuit in a way that does not fit the design/schematic. Shorts, improper component placement, missed solder joints, etc. Also could include 3.2.a- solder joints that "kinda" work, but are not mechanically strong... cold shorts, etc.. basically something that works sometimes, but could work loose on vibration, environmental changes, etc.

So for discussion point, I'd like to cover 2.2, 3.1, and 3.2

Quickest first- 3.1. As far as electronic kits go, I've never seen instructions as thorough as the eggtimer ones. I'm sure better ones exist, but given that @cerving has had his products out for several years, and have not seen any commentary about "I have no idea what it's telling me to do", I'd think that we could argue that the instructions are pretty solid. You could make a case for someone who's completely green reading it completely wrong, but are they likely to completely misread the instructions, and yet build an altimeter that is functional enough to stick in an av bay, seem like it's working, and still have an electronic deployment/ignition unplanned event? I see this kind of event as more likely being related to 2.2 (assembly failure) than instructions directly?

As for 2.2 and 3.2... let's assume that the person did the best of their abilities in soldering, but yet there is something wrong that they did not immediately detect while assembling.

Possible failure results here:
a. Altimeter does not function at all (doesn't turn on, doesn't do anything).
b. Altimeter turns on but does not function- basically beeps, but doesn't have any output (deployment charges, motor ignition, etc)
c. Altimeter turns on, seems to function, but does not function completely (drogue deployment charge goes off, but not the main, etc)
d. Altimeter turns on, seems to function, but functions are done at the wrong times (deployment goes off as soon as the altimeter is turned on, main comes out when it's supposed to be the drogue, etc)
e. Altimeter turns on, functions fine at one launch, but then fails at a different launch. For the sake of argument I'd like to limit this to point 3.2.a above (cold shorts, etc)

For the sake of argument, let's assume that these failure modes are specific to this altimeter, and not av bay assembly errors (#4 above).

I highly doubt for point a. that anyone with their right mind would stick this in an av bay and have it do any kind of critical function (more than a ride along).

For b, c, and d, I'd like to discuss these together. I think these are probably the crux of the discussion here.

These activities are mitigated in two possible ways:
1. Self checks on the startup of the altimeter. Basically the altimeter software is checking the circuit and warns the user if it finds something not kosher. This process should be the same for the user for all altimeters, not just self-assembled ones. They should be aware of error codes and what they mean, and react accordingly. I would also argue that anyone who has an altimeter will plug it in and test it out before putting any charges in it... be it commercial or self built.
2. User testing of the altimeter... using LEDs or whatever to check the actual deployment process in a safe manner. For sake of discussion, let's assume that this is not done with regularity or properly.

So basically we come down to the major failure points:

Point e- Altimeter is flaky- basically works some times, but not all the time. Unreliable, but maybe the unreliability is not noticeable to the user until it happens.
Point 2 above- Altimeter never really worked properly due to assembly errors, and wasn't caught until too late.

So then there's 3 failure modes, in my opinion
1. Fail hard- Negative event happens when it's not supposed to. Motor ignites at the RSO. Main parachute comes out when the rocket is on the rail, etc.
2. Fail hard(2)- Event fails to happen when it's supposed to. No drogue at apogee, etc.
3. Fail soft- Event fails to happen, but doesn't cause an issue. No second stage ignition, but rocket comes down safely under chute.

As for these events, I'll focus on 1+2 (although 3 is also a failure).

For this to be a problem with self assembled altimeters, we have to assume a failure point that is not caught by the software. In my layman's experience with electronics, 95% of the time this is related to "power" being somewhere where it shouldn't be. Basically there's a live voltage on the output connector. Or something isn't properly connected to ground where it should be.

So my question related to this are:
1. Is there ever a case where this is not caught by software.
2. And occurs in a failure mode that's specific to self assembly (soldering of components on the board)
3. And is not caught by the user beforehand?

I can't speak for everyone, but I think this case is very likely low, compared to people self assembling av bays above (#4 at the top), which is much more prone to error. I would also argue that any failure related to self assembly has a high linkage to #4 (self assembled av bay) and mitigating point #2- user testing of altimeter. These are things that should be checked regardless of where the altimeter came from.

Or add a switch. Queued up in the midst of 25 people while waiting to go to the pad is exactly when power should be physically disconnected.
Why would we wait until we have an accident to enact a rule?
I think the same points are being made on both sides of the discussion that have already been made and the same questions are being asked that were already answered somewhere in the past nearly 170 posts.

Speaknoevil said:

I beg to differ. Design is only a fractional contributor. It is about the logistics of a launch and traffic engineering. Take Airfest or Midwest Power with 300+ flyers. They all prep in parallel and get RSO'd almost at random. After leaving the RSO table or sometime later they get in line to get to the pads, say 15 to 20 deep. Regardless of the bank, often it takes 15 to 20 minutes to get the rockets ready to launch, sometimes quite a bit longer if there is an electronics issue. Currently it is only sliding the rocket on a rail/rod and activating a couple of switches and listening to beeps. Now, at least with high performance and staged rockets, maybe others, you will need to either do partial assembly at the pad or get on ladders or both. If you want to achieve the performance or flight profile this cannot be eliminated. Those 15 to 20 people may equate to 3 to 5 that need pad-adjacent table access, likely sequentially unless you have an extremely large table. The previous 15 to 20 minute bank loading will now double even if the 3 to 5 can finish assembly, climb, etc. in ~4 minutes each. My guess it will take much longer, again with those rocketeers under undo pressure and now prone to mistakes. So now the lines at the LCO table go from 15 to 20 deep to 30 to 40 deep, adding further pressure to the squeeze point at the bank. This intermediate pad-adjacent table solution is both unreasonable and dangerous. Let's say you eliminate the table, you still have 3 to 5 prepping on the ground, albeit in parallel, but under non-ideal conditions with pieces laying all over the pad bank--even more unreasonable and dangerous.

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I don't remember the abject chaos and unworkable launches before the invention of remote switches.

jderimig said:

I don't remember the abject chaos and unworkable launches before the invention of remote switches.

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You are right. I am not so much reacting to the use of a mechanical switch and the argument that that is more or less reliable than a remote switch. My comments are directly related to the suggestion that a pad prep area/table is set up. If everyone agrees to a switch and agrees not to encourage assembly/disassembly at the pads, then that would be fine.

Speaknoevil said:

You are right. I am not so much reacting to the use of a mechanical switch and the argument that that is more or less reliable than a remote switch. My comments are directly related to the suggestion that a pad prep area/table is set up. If everyone agrees to a switch and agrees not to encourage assembly/disassembly at the pads, then that would be fine.

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Exactly. That’s the same reason for my reply. That’s offered as a serious solution, and it’s obviously impractical. The practical solution seems to be to add a switch, but if you can’t do it before Saturday’s launch, I suppose the prep-at-pad solution is your only choice. Have fun with that!

And I guess I would add, in those cases of complexity/performance that require assembly/disassembly which cannot be avoided, then there should be an alternate path and safe area to the appropriate pads, see: https://www.rocketryforum.com/threa...ss-remote-switches.157373/page-4#post-1960144.

Most likely, the club is not going to allow you to take up a ridiculous amount of time at the pads. When people take too long at the pads at my club’s launches, the LCO tells them over the loudspeaker to clear out so they can launch the other rockets.

It’s been offered as a solution, but seriously, would your club allow it? If you can’t retrofit your rocket with a mechanical disconnect accessible from outside the rocket before your next launch, and you expect a long prep after check in, you might want to check with your club how they plan to handle it before you show up expecting a special prep area.

ThirstyBarbarian said:

...you might want to check with your club how they plan to handle it before you show up expecting a special prep area.

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I totally agree, but, and I say this with the utmost respect, the special intermediate prep idea was something offered up by the TRA President. That holds a lot more weight than your local club, and thus leads to my fear.

What keeps you from getting the rocket ready at your car. Turn off the electronics. Clear it with the RSO. Go back to your car. energize the wifi switch at your car. Carry it to the pad holding it vertically on the way there so it isnt pointing at anyone. Throw it on the pad and turn on the altimeter.

ThirstyBarbarian said:

Exactly. That’s the same reason for my reply. That’s offered as a serious solution, and it’s obviously impractical. The practical solution seems to be to add a switch, but if you can’t do it before Saturday’s launch, I suppose the prep-at-pad solution is your only choice. Have fun with that!

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No one is saying you have to fly on Saturday. Another option would be to take the time, make the necessary revision to your rocket/hardware and fly at the next launch.
Prep at the pad isn't an option in my mind.

We are an innovative group, There will be a whole slew of solutions to meet the new way of doing things.

The special prep table is interesting, but I've yet to see solutions/options that make it truly viable yet, but again - innovative group, they will come.

For me, It's a little easier, I was looking to add these devices to av bays that already have physical switches to remove them - physical switches stay and switch on the wifi switch/device.
However, my next builds will experiment with ways to eliminate the physical switch, with these goals in mind:
1. Be able to present the rocket to the RSO/LCO as flight ready as possible so they can analyze as necessary
2. With as little effort/hardware necessary, at the pad be able to power on wifi device by plugging in a battery, either through a hatch or other new/novel approach

At the end of the day, I think we can all agree on the underlying principle of the ruling, and we need to start focusing on the innovative solutions around them.

Dave

Alan15578 said:

Thanks,
I missed 1996 Safety Analysis of Manufacturers’ Maximum Recommended Liftoff Weight. Can you post a link so that I can download and read it?

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Sorry, don’t have any links. Try the NAR website.

SDramstad said:

I havent seen this much drama since visiting my 9 year old niece. It's not complicated. They dont want people with energized electronics involved with deployment charges crowded around the RSO table. Solution is to put a switch on the battery line JUST LIKE EVERY OTHER DUAL DEPLOY ROCKET THAT DOESNT USE WIFI! Which is still the majority of the fliers out there. Its simple, its safe and it works. No one needs to disassemble their rockets ebay at the pad. Put in a switch accessible from the outside of your ebay LIKE EVERYONE ELSE DOES!. You can even turn them on before its on the pad making it even easier then it is for everyone else.

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So will you reimburse me for the $100’s of dollars on electronic gear that a few days ago was not an issue? How about all the 3D printed A/V bays I have that incorporate a mag switch and now have to be scrapped? Or the time it will take to completely redo the bays on my 29mm and 38mm min diameter rockets, not not mention nearly ever other rocket I own that all use mag switches? I have over a dozen altimeters that are set up with mag switches, plus 4 WiFi switches, and a Protron. The three power perches I own will now require a solution for each ejection charge or I have to throw them in the trash.

Clearly you are unaffected by this rule change or you would not have such a cavalier attitude about a change made with no explanation or reasoning.

This rule affects nearly every rocket in my fleet, including all 4 I took to BALLS last year. It’s not a trivial “just add a switch”, it’s a complete redo of the way I have designed nearly every A/V bay in my fleet.

There is real money and a lot of time and energy at stake here for me, and I suspect many others. Not to mention the vendors. And I’ll ask yet again, why? Where is the reasoning why suddenly this approach is now unacceptable? That 1000 different solutions is better than just a handful? No one has answered that.


Tony

As a person who spends alot of time working on commercial aircraft electrical systems I think this change is based more on perceived risks without hard facts and understanding of how soild state switches work as opposed to actual risk. There is a very good reason commerical airliners transitioned to soild state contactors from mechanical ones years ago. The mechanical ones would fail with age the soild states out live the airplane. Mechanical switching is no more effective or safe than soild state switching and mechanical switches have substantially lower reliability

manixFan said:

So will you reimburse me for the $100’s of dollars on electronic gear that a few days ago was not an issue? How about all the 3D printed A/V bays I have that incorporate a mag switch and now have to be scrapped? Or the time it will take to completely redo the bays on my 29mm and 38mm min diameter rockets, not not mention nearly ever other rocket I own that all use mag switches? I have over a dozen altimeters that are set up with mag switches, plus 4 WiFi switches, and a Protron. The three power perches I own will now require a solution for each ejection charge or I have to throw them in the trash.

Clearly you are unaffected by this rule change or you would not have such a cavalier attitude about a change made with no explanation or reasoning.

This rule affects nearly every rocket in my fleet, including all 4 I took to BALLS last year. It’s not a trivial “just add a switch”, it’s a complete redo of the way I have designed nearly every A/V bay in my fleet.

There is real money and a lot of time and energy at stake here for me, and I suspect many others. Not to mention the vendors. And I’ll ask yet again, why? Where is the reasoning why suddenly this approach is now unacceptable? That 1000 different solutions is better than just a handful? No one has answered that.


Tony

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I do sympathize with you a bit but with all of your experience with building Ebays, wiring up the electronics, testing setting up and flying your rockets you find adding a single switch on your battery to be an insurmountable task? Really???

dvdsnyd said:

No one is saying you have to fly on Saturday. Another option would be to take the time, make the necessary revision to your rocket/hardware and fly at the next launch.

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Well, yes, but reality sets in. Last weekend I pulled two HPR rockets and two motors out of storage in anticipation of our first launch of the season this Saturday/Sunday. I have no way of getting other rockets at this point and have limited prep time before the launch. One of the rockets is now "borderline" non-compliant (depending on how you interpret this thread). I don't want to drive 3 hours from my current location to fly only one rocket, and yes, potential flyers have been asked by the local club to verify compliance to this new rule. Although I believe they were going to make an exception because it is a magnetic switch instead of a wi-fi switch, I still hope to be fully compliant come Saturday, as I found and ordered special connectors from Amazon last night that would allow access to a break point in the av-bay. Prime delivery says it will be here tomorrow afternoon.

Steve Shannon said:

This revision, which takes place immediately, requires that all devices which control staging or energetic charges must be physically disconnected from power (add a battery switch) or must have their initiators mechanically disconnected from potential power sources while being transported or when presented for pre-flight inspection. Such disconnection may be done between the pyrotechnic battery and the device or between the device and any pyrotechnic initiator device(s). Either mechanical switches or complete physical disconnections may be used

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Add the switch and you can ignore everything after that "OR"

SDramstad said:

Add the switch and you can ignore everything after that "OR"

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Adding a switch adds a failure point and also defeats the purpose of the wireless switch. Why have two switches for the same circuit at that point the wireless switch just becomes a gimmick for entertainment. It is literally just one more thing to forget and potentially cause a crash

John Williams said:

As a person who spends alot of time working on commercial aircraft electrical systems I think this change is based more on perceived risks without hard facts and understanding of how soild state switches work as opposed to actual risk. There is a very good reason commerical airliners transitioned to soild state contactors from mechanical ones years ago. The mechanical ones would fail with age the soild states out live the airplane. Mechanical switching is no more effective or safe than soild state switching and mechanical switches have substantially lower reliability

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John Williams said:

Adding a switch adds a failure point and also defeats the purpose of the wireless switch. Why have two switches for the same circuit at that point the wireless switch just becomes a gimmick for entertainment. It is literally just one more thing to forget and potentially cause a crash

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As a former Reliability Engineer I love your resolve and totally agree with you, but I just want to warn you, this path will fall on deaf ears and lead to frustration.

Frankly this reminds me of when the government put huge restrictions on rocket motors after September 11th that almost crippled this hobby because of what some people thought were risks that were not grounded in hard facts

I'm flying with ROC on Saturday, bringing only one rocket. I didn't have time to put in a mechanical switch, so it's twist-and-tape on the power to the deployments... with LOTS of tape, wrapped around the airframe a few times. I do not want this coming apart in flight.

On another front, has anyone done any kind of actual study on the reliability of the different types of commonly-used switches in hobby rocketry? The only information that I've ever seen has been anecdotal. Electronic parts have detailed spec sheets that give you the characteristics under varying physical conditions (temperature, vibration, acceleration, etc.), other than the Schurter 033.4501 voltage selector switch there are generally no specs for the generic switches that seem to be in popular use. The Schurter parts complies with IEC 60068-2-6 for vibration and shock... unfortunately, it's $300 to get a copy of the spec.

djs - there is another failure mode that people are overlooking that this ruling will help to mitigate. Eggtimer products are great, IMHO, but a failure mode is that they will not fire charges if the voltage drops too low. This could be a risk if you load up, check in with the RSO, and there is a long queue (say hours ) to the pad. Lipos should give you 3 hours, but still ... it's a risk. Not turning on until just prior to loading will help mitigate this risk.

John Williams said:

As a person who spends alot of time working on commercial aircraft electrical systems I think this change is based more on perceived risks without hard facts and understanding of how soild state switches work as opposed to actual risk. There is a very good reason commerical airliners transitioned to soild state contactors from mechanical ones years ago. The mechanical ones would fail with age the soild states out live the airplane. Mechanical switching is no more effective or safe than soild state switching and mechanical switches have substantially lower reliability

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I don't think anyone is debating the ultimate capability potential of semi-conductor switches. But in actual devices in use now, there is no comparison between the design and manufacturing standards of aerospace electronics and our hobby electronics.

curtisheisey said:

djs - there is another failure mode that people are overlooking that this ruling will help to mitigate. Eggtimer products are great, IMHO, but a failure mode is that they will not fire charges if the voltage drops too low. This could be a risk if you load up, check in with the RSO, and there is a long queue (say hours ) to the pad. Lipos should give you 3 hours, but still ... it's a risk. Not turning on until just prior to loading will help mitigate this risk.

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Good point, but it's a failure that's also applicable to all altimeters. To be honest though, I'll be putting a switch on all my wireless stuff for this exact reason.

jderimig said:

I don't think anyone is debating the ultimate capability potential of semi-conductor switches. But in actual devices in use now, there is no comparison between the design and manufacturing standards of aerospace electronics and our hobby electronics.

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Fair enough but that rings true for mechanical switches as well. Frankly this smacks of people who don't trust wireless switches because they don't understand them and can't see how they function. But again show me the proof that a mechanical switch is more reliable and safer.